In recent years, research on electrochemical cells has actively been conducted. For example, polymer electrolyte membrane electrolysis cells (PEMEC) among electrochemical cells are superior in responsiveness to renewable energy of photovoltaic power generation and the like and so are expected to be utilized for generating hydrogen of large-scale energy storage systems. In order to ensure sufficient durability and electrolytic characteristics, noble metal catalysts such as platinum (Pt) nanoparticle catalysts for the cathode of PEMEC and iridium (Ir) nanoparticle catalyst for the anode are commonly used.
One big challenge for widespread use of PEMEC is the cost reduction by reducing the amount of use of noble metal catalysts. In particular, a significant reduction of the amount of noble metal catalyst used, which is used as an oxygen generating catalyst of the anode, is demanded.
Also, high activity of ruthenium (Ru) has been reported in oxygen generating catalysts. However, it becomes difficult to maintain oxygen generating activity and durability with dissolution of Ru accompanying an electrode reaction of water electrolysis. Therefore, a catalyst having high oxygen generating activity and durability is demanded.